Method for producing a peroxynitrate

ABSTRACT

Contacting a cycloalkene of the formula:   WITH A MIXTURE OF DINITROGEN TETROXIDE AND OXYGEN TO PRODUCE PEROXY NITRATES OF THE FORMULA:   WHICH PEROXY NITRATES MAY BE CONVERTED TO ALKANDIOIC ACIDS.

[72] Inventors Emma 15%. Mammal;

'Kmfldl S. Sm; mm L. MB 6!? mm, PHI. [21 App]. No. 031,793 [22] Filed Feb. w, 1069 [45] Patented Nov. 116, M71 [73] Assignee 'licmnm Hm.

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[52] USJCI! 260/6,

[51] Int. Cll. C07c 77/00 [50] Weld oi Search 260/610 B. 610 R, 466, 644, 645

Primary Examiner-Bemzrd Helfin Assistant Examiner-W. B. Lone Attorneys- K. E. Kavanagh and Thomas H. Whaley ABSTRACT: Contacting ayycloalkene of the formula:

CH-O ONO;

R-CH-NO2 v vhich peroxy nin rates may be convened to alkandioic acids.

h/illE'lill-lltiilll) litlth lPlttMtlJCWG A MENU l l l a t This application is a division of Application Ser. Number 541,431 filed March 10, 1966 and now US. lPat. No. 3,466,326 which in turn is a continuation-in-part of Ser. No. 466,816 filed June 24, 1965 and now US. Pat. No. 3,415,856.

Parent application, Ser. No. 466,816, represents our discovery of a method of producing alhanoic and alkanedioic acids respectively from aliphatic alltenes and alltenoic acids together with their corresponding nitroperoxy and nitroalhanone intermediates by reacting an aliphatic olefin with a mixture of nitrogen tetroxide and oxygen to form the nitroperoxy intermediate with the subsequent treatment of the nitroperoxy intermediate with particular denitrating compounds to form the nitroalltanone intermediate which in turn can be hydrolyzed in the presence of an acid catalyst to form allcanoic and alkanedioic acids.

W e have discovered, and this constitutes our invention, that broadly the method set forth in our parent application, Ser. No. 466,816, is suitable for converting cycloalltenes into nitrocycloallrylperoxy nitrates, nitrocycloalltanones and allranedioic acids. More specifically the overall method and submethods of the invention are defined as follows.

FilRS'l STAGE The first stage of the overall method of the invention comprises simultaneously contacting a cycloallrene of the general formula:

where R is a polyrnethylene radical of from 1 to 10 carbons or a substituted polymethylene of 2 to 10 carbons containing one or more stubstituents selected from the group consisting of alltyl, arlyl and carboxypolymethylene,-(Cl-lQ COOl-i, of up to 20 carbons or more with a mixture of dinitrogen tetroxide and oxygen to form a nitroperoxy intermediate of the general formula:

CH-O ON z R--CHNO;;

where it is as heretofore defined. Preferably IR is polymethylene of from 3 to 5 carbons, most preferably 4.

The reaction temperature employed is advantageously between about 40 and 20 C. Higher reaction temperatures tend to facilitate the decomposition of the peroxynitrate product and at temperatures below the prescribed range the dinitrogen tetroxide would not function clue to its inability to dissociate into monomeric nitrogen dioxide.

The reactant mole ratio of cycloalltene to oxygen to dinitrogen tetroxide in the reaction is advantageously between about 1:l:0.5 and 1:30:15. However, the critically important aspect of the reactant ratio is the maintenance of the mole ratio of oxygen to dinitrogen tetroxide of at least about 2:1 during the entire reactant contacting in the first stage. if the ratio of reactant oxygen to reactant dinitrogen tetroxide falls substantially below the 2:1 ratio during the reaction, a mixture of nitroalhyl nitrates and nitrites and dinitro compounds results rather titan the desired nitrocycloalltylperoxy nitrate. Excess oxygen even in excess of the stated ranges does not deleteriously affect the reaction.

The reaction time is normally between about one-half and hours although longer and shorter periods may be employed.

The formed nitrocycloalltylperoxy nitrate is recovered, if desired, by standard means, e.g., a fractional distillation such as stripping the volatiles from the reaction mixture below about 0 C. under reduced pressure.

it is to be noted that the nitrating agent, dinitrogen tetroxide, is actually an equilibrium mixture of dinitrogen tetroxide and nitrogen dioxide with the equilibrium being driven essentially to percent dinitrogen tetroxide at 0 C. and essentially 100 percent nitrogen dioxide at C. The term dinitrogen tetroxide" as used herein denotes the equilibrium mixture as well as the pure N 0, compound.

Under advantageous conditions, the diniu'ogen tetroxide is normally introduced into the reaction system at a rate between about 0.002 and 0.02 grams/minute/gram cycloalkene. However, the actual rate depends in large measure upon the rate of heat removal from the reacfion system.

The oxygen employed may be in the pure form or in the diluted form such as air or in admixture with inert gases such as nitrogen and argon. Under advantageous conditions, the oxygen is introduced into the reaction system at a rate between about 5 and 40 mlsJminute/grarn cycloalltene.

To promote contact of the reactants in the first stage the reaction is desirably carried out under conditions of agitation in the presence of an inert liquid diluent having boiling points between about 30 and 100 C. such as nhexane, n-heptane, carbon tetrachloride and diethyl ether.

The contact of the nitrogen dioxide and oxygen with the cycloalltene is accomplished by standard means such as combining streams of oxygen and gaseous dinitrogen tetroxide, or by passing a stream of oxygen over or through liquid dinitrogen tetroxide at a temperature between about 0 and 21 C. to form a mixture of dinitrogen tetroxide and oxygen which in turn is bubbled through or otherwise contacted with I the cycloalkene. Another means of introducing oxygen and dinitrogen tetroxide is the simultaneous introduction of separate streams of the dinitrogen tetroxide and oxygen into the cycloalltene keeping in mind that the ratio of oxygen to dinitrogen tetroxide in the reaction zone should be maintained at at least about 2: 1.

The formed peroxynitrate can be isolated from the diluent (if used) and excess dinitrogen tetroxide and volatile byproducts by standard means such as vacuum distillation.

Examples of the cycloallcenes contemplated herein are cyclopentene, cyclohexene, cycloheptene, 3-methyl cyclopentene, 4-methyl cyclohexene, 4-phenyl cyclohexene, 3-carboxytetramethylene cyclohexene.

Examples of the intermediate nitrocycloalltylperoxy nitrate products contemplated herein are 2-nitrocyclohexylperoxy nitrate, Z-nitrocyclopentylperoxy nitrate, 2-nitrocycloheptylperoxy nitrate, 2-nitro-4-methyl cycl-ohexylperoxy nitrate, 2- nitro-3-methyl cyclopentylperoxy nitrate, 2-nitro-4-phenyl cyclohexylperoxy nitrate and 2-nitro-3-carboxytetramethylene cyclohexylperoxy nitrate.

SECOND STAGE in the second stage of the overall method the nitrocycloalltylperoxy nitrate formed in the first stage of the formula:

where R is as heretofore defined, is then contacted with a denitrating agent such as those selected from the group consisting of R: N- C O,

II c where R is as heretofore defined. The reaction of the second stage is more or less instantaneous after addition of reactants. The particular mode of bringing the reactants together depends on many things such as molecular weight of reactants and reactivity of peroxy material. Normally, the contacting is accomplished by slow addition of the more reactive peroxy intermediate to the denitrating agent for best temperature control.

The nitrocycloalkanone intermediate product can be recovered by standard recovery processes, for example, via forming derivatives, filtration, extraction or fractional distilla tion and combinations thereof.

Normally, inert diluent is not employed in the second stage of the overall process of the invention if one of the reactants is in liquid form. However, if both reactants are in the solid stage then to facilitate interaction inert liquid diluent is employed, for example, inert liquid diluent having a boiling point between about 30 and 100 C. such as pentane, hexane, carbon tetrachloride and diethyl ether. Agitation of the reaction mixture is also a preferred condition.

Specific examples of the denitrating agents contemplated herein are dimethyl formamide, diethyl forrnamide, dimethyl acetamide, dimethyl sulfoxide, diethyl sulfoxide, tetramethylurea, tetraethylurea and hexamethylenephosphoramide.

Specific examples of the nitrocycloalltanone products in the second stage of the overall process are Z-nitrocyclohexanone, 2-nitrocyclopentanone, 2-nitrocycloheptanone, 2-nitro-3- methyl cyclopentanone, 2-nitro-4-phenyl cyclohexanonc 2- nitro-3-carboxytetramethylene cyclohexane.

THIRD STAGE in the third stage of the overall method the nitroltetone of the formula:

II R--OH-NO2 where R is as heretofore defined, recovered from the second stage is contacted with water in the presence of an acid member selected from the group consisting of mineral acid, hydrocarbon sultonic acid and haloacetic acid having a dissociation constant in excess l0 '2 at a temperature between about 0 and l50 C., advantageously in a mole ratio of nitrocycloalltanone to acid member of at least about M and up to l:l0 and higher, in a mole ratio of nitrocycloallcanone to water of at least about 1:2 and up to 1:20 and higher to form a carboxylic acid of the general formula:

HOCCRCOOH where R is as heretofore defined.

This third stage of the reaction is normally conducted for a period in the range of minutes to several hours. However, the actual reaction time will be dependent in large measure on the particular acid strength of the acid member employed. Under preferred conditions, the reaction mixture is agitated in order to facilitate contact between the reactants. lFurtl'ler, if both the acid and the nitrocycloalkanone are of a solid nature in order to afford better reactant contact inert liquid diluent is advantageously employed. For example, inert liquid diluent having a boiling point between about 50 and 150 C., such as acetic acid.

The water contact in the third stage is normally accomplished by first forming the final nitrocycloalkanone acid reaction mixture and then contacting with an excess of water, e.g., pouring said reaction mixture into a stoichiometric excess of water maintained at a temperature of about 0 C.

The carboxylic acid product is then recovered by standard means such as by filtration and/or extracting the formed carboxylic acid with ether followed by stripping off the extractant from the extract solution to leave the carboxylic acid as residue. Examples of the final carboxylic acid products contemplated herein are adipic acid, glutaric acid, pimelic acid, 2- methyl pentanedioic acid, 3-methyl hexanedioic acid, 3-phenyl hexanedioic acid and 3-carboxy tetrarnethylene hexancdioic acid.

Specific examples of the acid catalyst contemplated in stage three are sulfuric acid, phosphoric acid, nitric acid, trichloroacetic acid, methane sulfonic acid and ethane sulfonic acid. The acids employed are advantageously of an acid strength in respect to aqueous dilution of at least about 70 wt. percent of the concentrated state.

The combination processes and subcombination processes (Stages I, ll, ill) of the invention may be further defined by the following equations utilizing cyclohexane, tetramethylurea Hereinafter and hereinbefore superatrnospheric and subatmospheric pressures are contemplated whenever they are required to insure desired liquidity and separation. Further, the term polymethylene is intended to include methylene as well as a plurality of methylene groups.

The following examples further illustrate the overall method and submethods of the invention but are not be be construed as limitations thereof.

EXAMPLE I This example illustrates the first stage of the overall method.

To a magnetically stirred flask maintained at 0 C. in an ice bath there was charged 3.8 mls. of cyclohexene and 60 mls. of carbon tetrachloride. Through the charged cyclohexene-carbon tetrachloride mixture there was bubbled a stream of a mixture of dinitrogen tetroxide and oxygen in a mole ratio of about 1:14 at a rate of 56.5 mls./minute, said stream formed by passing a stream of oxygen over dinitrogen tetroxide at a rate of 56.5 mls./minute. This introduction lasted for a 6-hour period. A total of 2.4 mls. of dinitrogen tetroxide was added. At the end of the dinitrogen tetroxide-oxygen treating period, the carbon tetrachloride and excess nitrating agent was removed via vacuum at 0 C. under 18 mm. Hg. The residue was an almost colorless oil and was determined by infrared analysis to be Z-nitrocyclohexylperoxy nitrate.

EXAMPLE ll This example illustrates the second stage of the overall method, namely, the conversion of the peroxy nitrate compound of example 1 into the corresponding nitrocyclohexanone.

To a magnetically stirred flask there was added 20 mls. of tetramethylurea. Tothe flask there was then added dropwise sgez oso all of the peroity nitrate pitiiici main taining the temperature between about 20 and 25 C. by control of the addition rate and the use of an ice bath. The reaction solution turned yellow and was very exothermic during the addition. When addition was complete the formed nitrolretone in the resultant reaction solution was isolated therefrom in purified form by first diluting the resultant solution with 50 mls. of ether followed by the addition of sodium bicarbonate to the other solution until a visual (C emission) reaction ceased to take place, i.e., until all the nitric acid byproduct was destroyed. The nitroltetone was then precipitated from the neutralized ether solution as its orange morpholine salt in an amount of 5.5 grams by the addition of morpholine to said solution with stirring in an amount of 3.5 mls. The precipitated morpholine salt was separated from the other solution and the nitroltetone was regenerated from said salt by dissolving said salt with dilute aqueous hydrochloric acid and extracting the nitroltetone with ether, evaporating off the ether to give 2.10 grams of a yellow oil product which was identified by infrared spectrum analysis as Z-nitrocyclohexanone.

EXAMPLE Hill This example illustrates the third stage of the overall method of the invention, namely, the conversion of the nitrocycloalltanone product of example llll into the corresponding alitanedioic acid.

To it) this. of concentrated sulfuric acid at 20 C. there was added 0.78 grams of Z-nitroeyclohexanone formed in example Ill. The resultant acid solution was stirred one-halt an hour at 20 C. and was then poured on ice and continuously extracted with ether for 5 hours. The ether was distilled from the ether extract solution leaving 0.23 of a white residue having a melting point or l40-l46 C. The aqueous mixture was again continuously extracted with ether for 24 hours. The ether was distilled from the second ether extraction leaving a white' R GIL-N02 where R is selected from the group consisting of polymethylene of from 1 to 10 carbons, and polymethylene of from 1 to 10 carbons containing at least one substituent, said substituent selected from the group consisting of alkyl, aryl and carboxypolymethylone comprising simultaneously contacting cycloalkeno of the formula:

R CH

where R is as heretofore defined, with a mixture of dinitrogen tetroxide and oxygen at a temperature between about -40 and 20 C. while continuously maintaining the ratio of said oxygen to said dinitrogcn tetroxide during said contacting at least about 2:1.

BIA method in accordance with claim 1 wherein said contasting is conducted utilizing a mole ratio of cycloalkene to oxygen to dinitrogen tetroxide of between about l:l:0.5 and 1:30:1-5.

3. A method in accordance with claim 2 wherein said cycloalkene is cyclohcxene and said pcrioxy nitrate compound is Z-nitrocyclohexylperoxy nitrate.

d. The peroxy nitrate compound prepared by the method of claim ll.

5. The peroxy nitrate compound prepared by the method of claim 2. l

e. Z-nitrocyclohexylperoxy nitrate.

:3 I?! & 

2. A method in accordance with claim 1 wherein said contacting is conducted utilizing a mole ratio of cycloalkene to oxygen to dinitrogen tetroxide of between about 1:1:0.5 and 1:30:1-5.
 3. A method in accordance with claim 2 wherein said cycloalkene is cyclohexene and said perioxy nitrate compound is 2-nitrocyclohexylperoxy nitrate.
 4. The peroxy nitrate compound prepared by the method of claim
 5. The peroxy nitrate compound prepared by the method of claim
 2. 6. 2-nitrocyclohexylperoxy nitrate. 